title: Extension of imaging depth in two-photon fluorescence microscopy using a long-wavelength high-pulse-energy femtosecond laser source.
abstract: We experimentally demonstrate, for the first time to the best of our knowledge, two-photon fluorescence imaging with a femtosecond optical parametric amplifier. In particular, we systematically compare the imaging depths of two-photon fluorescence microscopes based on three different excitation sources, including a femtosecond oscillator, a femtosecond regenerative amplifier and the optical parametric amplifier. The results show that the optical parametric amplifier can greatly extend the penetration depth by approximately 227% as compared with that obtained with the femtosecond oscillator due to effective suppression of scattering at longer wavelength and enhanced excitation efficiency enabled by higher pulse energy.
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, P.O. Box 800-211, Shanghai 201800, China.
authors.forename: C
authors.initials: C
authors.lastname: Wang
authors.forename: L
authors.initials: L
authors.lastname: Qiao
authors.forename: F
authors.initials: F
authors.lastname: He
authors.forename: Y
authors.initials: Y
authors.lastname: Cheng
authors.forename: Z
authors.initials: Z
authors.lastname: Xu
mesh_terms: D000669:Amplifiers, Electronic; D007089:Image Enhancement / Q000379:methods*; D007834:Lasers; D018613:Microscopy, Confocal / Q000295:instrumentation / Q000379:methods*; D036641:Microscopy, Fluorescence, Multiphoton / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D017785:Photons